This section is intended to provide a background to the various embodiments of the technology described in this disclosure. The description in this section may include concepts that could be pursued, but are not necessarily ones that have been previously conceived or pursued. Therefore, unless otherwise indicated herein, what is described in this section is not prior art to the description and/or claims of this disclosure and is not admitted to be prior art by the mere inclusion in this section.
Due to the increasing demand to enhance wireless capacity and due to lack of availability of spectrum in lower frequency range (e.g. 800 MHz-3 GHz), the use of frequencies in 10's of GHz range is being investigated. For the future wireless network, investigations are going on to explore higher frequency bands, for instance, in the range of 30 GHz, 60 GHz and 98 GHz. At this frequency, a very large bandwidth of spectrum is available. This means both operating frequency and bandwidth for the future networks are expected to be much higher than those for legacy wireless networks.
However, due to large signal attenuation with respect to path loss, the network operating over such high frequencies is supposed to cover small areas with densely deployed radio access nodes (ANs). Considering that such dense deployment is particularly useful to provide sufficient coverage for indoor/hot areas, it has been agreed to exploit Ultra-Density Network (UDN) or Super Dense Network (SDN), which is also referred to as millimeter Wave-Radio Access Technology (mmW-RAT), for the future wireless system.
Currently, it is supposed that the total carrier bandwidth of the mmW-RAT can be up to 1 or 2 GHz. This bandwidth can be composed by a number of sub-band carriers of a certain bandwidth, e.g. 100 MHz. By way of example, FIG. 1 illustrates one mmW-RAT carrier with 4 sub-bands. The smallest resource grid in the figure is an Atomic Scheduling Unit (ASU), which is also called a resource block (RB) and corresponds to a subband in the frequency domain and to a subframe in the time domain.
To allocate the available resources, a scheduling based resource allocation scheme may be applied by configuring a Central Control Unit (CCU) which is shared by a cluster of ANs and relied on to allocate resources to different radio links. To be specific, the CCU configures, for each of the radio links associated with the ANs, a template frame indicating multiple types of resources allocated to the radio link.
For illustration, an exemplary radio network where the scheduling based resource allocation scheme may be implemented is depicted in FIG. 2. In addition to AN1-AN4, the network comprises a CCU responsible to determine, for radio link 1, a template frame based on relevant measurements and/or data rate requests from peer communication devices (i.e., AN1 and User Equipment 1 (UE1)) on radio link 1. Further, the template frame determined for radio link 1 can be updated by the CCU during a communication session according to various varying factors, such as interference measurements and/or data rate requests from radio link 2 which is the neighboring link of radio link 1. Likewise, the CCU determines a template frame for radio link 2 and updates the template frame by taking into account radio link 1's impact on radio link 2.
Further details of the template frames configured for radio links 1 and 2 are given in FIG. 3. Taking the template frame configured for link 1 as an example, the template frame specifies, for link 1 on which both downlink communications from AN 1 to UE 1 and uplink communications from UE 1 to AN 1 occur, dedicated resources, shared resources (also known as opportunistic resources) and prohibited resources, as illustrated in FIG. 3. In case AN 1 on link 1 is able to be aware of unused dedicated radio resources allocated to link 1's neighboring link (in this example, link 2), it can also locate such resources on the template frame configured for link 1, as illustrated in FIG. 3.
On the dedicated resources allocated to a radio link, data transmissions between peer communication devices on this link can be performed with high reliability. To be specific, if link 1 is allocated with certain dedicated resources, link 1 will have the highest priority to access these resources while link 2 shall control its interference to link 1 on these resources. However, in case certain dedicated resources allocated to link 2 are not being used by the peer communication devices on link 2, AN 1 can advantageously schedule its data transmissions from and/or to UE 1 on these resources.
On the shared resources allocated to a radio link, data transmissions of lower reliability can be performed between peer communication devices on this link to achieve enhanced data rate. To be specific, if link 1 is allocated with certain shared resources, both link 1 and link 2 can access these resources and the use of these resources by one of link 1 and link 2 may produce interference to the other.
On the prohibited resources for a radio link, data transmissions are not allowed to be performed between peer communication devices on the radio link.
After receiving the template frame configured by the CCU for link 1, AN 1 can then make various scheduling decisions for its transmissions to and/or from UE 1 (namely, for downlink and uplink communications on link 1). By way of example, AN 1 can determine a transmission power, a Modulation and Coding Scheme (MCS), a specific resource allocation, a transmission rank, a redundancy version or the like for either the downlink or the uplink communications on link 1. After determining the scheduling information, AN 1 can then notify the determined scheduling information to UE 1 in a scheduling command (also referred to as downlink assignment in downlink) so that UE 1 can receive downlink transmissions from AN 1 according to the scheduling information. Alternatively, AN 1 may notify the determined scheduling information to UE 1 in a scheduling grant in response to receiving a scheduling request from UE 1, so that UE 1 can transmit uplink transmissions to AN 1 according to the scheduling information.
According to the prior art solution for signaling the scheduling information to the UE, AN 1 generates and transmits to UE 1 a scheduling command or a scheduling grant (hereinafter collectively referred to as a scheduling message) for scheduling only one DL or UL data transmission in one DL or UL subframe on one carrier on link 1. As a result, the same set of data transmission configurations indicated by the scheduling message (including a transmission power, an MCS, a specific resource allocation, a transmission rank, a redundancy version or the like) has to be used for all radio resources on link 1. This undesirably leads to inefficient use of radio resources, because the optimal data transmission configuration, which allows for the highest possible spectral efficiency under the condition that the target acceptable transmission failure rate is satisfied, is different for different types of radio resources on link 1.